The Attribute of Light Science Still Can't Explain

Double slit experiment, and quantum light paradox. Get 60% off your Babbel subscription: go.babbel.com/t?bsc=1200m60-y...
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#light #quantum #astrum
photon energy, polarized lenses, double slit experiment, quantum

[@astrumspace]

If you liked this, you may like my other video on the weirdness of quantum particles here: kzbin.info/www/bejne/bHeznGapgdimhrM Also, thanks to Babbel for sponsoring today's video. Get 60% off your Babbel subscription: go.babbel.com/t?bsc=1200m60-youtube-astrum-jun-2023&btp=default&KZbin&Influencer..astrum..USA..KZbin

[@charlesbrightman4237]

QUESTIONS (Photons): Okay, 'wavelength' and 'frequency' appear to exist: 'Wavelength': How long the photon is in 'space'. 'Frequency': How many cycles per second in 'space'. 1. What exactly is 'space' that the photon exists in, OR does the photon itself make up 'space'? 2. What exactly is 'time' that there can be 'cycles per second'? 3. A photon is usually depicted in a sine wave pattern with the 'e' and 'm' energy fields 90 degrees to each other. The 'e' and 'm' energy fields go out together and come back in together, over and over and over, doing so even across the vast universe as far as we can see. Where does the energy in the energy fields go when both the 'e' and 'm' energy fields go to zero? And what causes the 'e' and 'm' energy fields to come back to 'full' from zero? Over and over again over vast distances.

[@franciscooyarzun2637]

You did not mention orbital angular momentum: the weirdest of all (IMO) !

[@Kaydin66]

"Light behaves differently when you're not looking at it." This is false. You're spreading unscientific views for clicks. Do better. This is your job.

[@StephenGillie]

If you're not even going to research Thomas Young's experiment, then it's Just Another Bad Science Video. The reason our math describes waves instead of particles is because our mathematicians gave up trying to find other ways, and instead spent their time trying to prove or disprove Einstein. Physicists need to do more physics, historians need to learn more history, and DJs gotta dance more.

[@joshpage4547]

What if light isn't actually moving from place to place as a photon and rather it is vibrating a particle-like point in static space, this would enable both particle and wave behavior. The path of light would be a coalescing wave of vibrations (frequency) from particle to particle.

[@timhaldane7588]

The creepiest part of all this is what the delayed choice experiments seem to prove: reality not only waits to "decide" a particle's properties until an interaction takes place, it then *retroactively* rewrites past uncertainties so everything remains consistent. The universe is constantly error-checking itself with a mechanism not bound by the arrow of time the same way that we are. We're caught up in the current that flows from past to future, but information itself ripples out in both (all?) temporal directions.

[@10418]

True, because time doesn’t exist and if so, is more like a layer

[@godless-clump-of-cells]

​@@10418 Time exists; it's just relative.

[@jmc22475]

Or the future is predetermined

[@andoapata2216]

This simulation uses recursion to simplify rendering reality , a common software solution .

[@timhaldane7588]

@@nadsenoj8719 what kind of "similar effect" do you mean, though? It sounds like you're trying to describe some kind of hidden variable relationship with the wave function acting as a mediator. Okay, but how? The problem is that the wave function, this math we can use to accurately describe the correlated relationship between entangled particles... we don't know what it represents in physical reality. Whether the math is merely descriptive of something deeper, or the wave function actually does represent some kind of causal thing in the world, it must be describing something real, right? (The phrase "probability waves" frankly sounds to me like Descartes's claim that a nonphysical soul controls our physical body: mystical nonsense masquerading as an explanation.) The nonlocal nature of the wave function cries out for explanation. Either it connects phenomena instantly across space, making space somehow unreal, or it isn't bound by time. Personally, I think we have a lot more reasons to think time's arrow only applies to macroscopic objects than to think distance isn't real except that it also is. But that's me.

[@ncb5455]

Have seen dozens of explanations of the two-slit experiment and every single time walked away unconvinced I actually understood it. Until this video. Top notch stuff as always.

[@UpperDarbyDetailing]

Answers with Joe has a good video on it too

[@thebogsofmordor7356]

This was a darn good explanation!

[@BigWhoopZH]

Me too, but I still prefer double slit experiments conducted in the bedroom.

[@alexbrestowski4131]

Definitely took me a few different explanations until I felt like I had a good understanding of the double slit

[@whermanntx]

The problem with the way people explain it is they don't tell you how the detector interacts with the photon as it passes through its respective slit. It's only able to detect it because it interacted with the photon in some way, collapsing it's wave probability function into a deterministic one. The detectors aren't some magic devices that can see a photon pass through without interfering with the photon.

[@cornishcactus]

I heard ages ago that light always takes the shortest path between two points. Refraction IIRC was caused by light slowing down in the medium of water but it bends in such a way that it still finds the quickest path to it's destination. Gravitational lensing is caused by light taking the quickest possible route which still happens to be being bent in spacetime around a gravitational object. This almost implies light knows it's destination.

[@jameshughes6078]

3 blue one brown just came out with a great video on refraction/change of speed in media, highly recommend checking it out

[@brandonhealy7158]

What is light’s destination? That is very poignant and thought-provoking, that it already knows it’s destination before it embarks on its journey.. very scary and otherworldly indeed. 😦

[@watema3381]

@@brandonhealy7158God is Light, it's literally written. Light is everywhere, in one shape or another

[@annoyingbstard9407]

If I throw a stone hard enough the same applies. So a stone knows where it’s going too.

[@kaylamorris283]

The recent time slit experiment pretty much showed that light is, in a sense going into the future mapping its path then taking it. The journal article was published I think the beginning of this year

[@stevemawer848]

There's clearly more to light than meets the eye! 🙂 Excellent video, thanks.

[@HypnosisBear]

Nice Pun! Made my day! Thank you!

[@davideaston1139]

Firstly NO ONE ever see's light, only illumination, second, the mathematicians in the cult of bumping particles have NEVER defined what energy is and have NEVER defined what a field is, they don't understand what light is or does, get yourself over to uncle Kenny at Theoria Apophasis if you want to really know what light is...otherwise you can stay ignorant

[@craig7350]

.. that gave me a warm feeling all over.

[@mozzjones6943]

@@HypnosisBear He used that pun in the video

[@MikeBUSA]

Just to be clear, photons (light) are not the only particles that behave this way through the double slit experiment. This has been demonstrated with electrons, neutrons, atoms, and even some molecules. Also, if you move those detectors right at the detection screen and leave them off until after the particle passes through the slits, but turn them on just before the particle hits the detector, you get the exact same results. This is mind blowing. It's almost like the particle goes back in time.

[@akgonen60]

i seen that on a vided once .. if you were to send a electron thru the slits it enters the slits leaving the gun as a wave but the second yoiu observe the wave before it hits the wall or before it hit the slits the electrons become particle not only before they hit the sliuts but they ended up leaving THE GUN as a particle ... so the electrons almost instantly went back intime before it even left the gun to appear as a particle just insane

[@blugreen99]

Delayed choice xpt debunked by Sabine Hossenfelder

[@wlockuz4467]

How would you turn on the detector just before the particle hit the detector? Wouldn't you have to perform that action faster than speed of light for it to actually work?

[@MikeBUSA]

@@wlockuz4467 , no - not at all. Electronics are super fast now. There is a finite amount of time it takes the particle to leave the source, through the slits, and reach the detector. It's fast, but not so fast they can't switch quickly enough. It's called the delayed choice experiment - not to be confused with the delayed choice quantum eraser. The simpler setup only deals with one particle - not an entangled pair where there is some dispute about those results.

[@rohitkhanna]

@@wlockuz4467 No. Think about it........

[@xyzabc4574]

That's exactly how I'd code light to behave if I were trying to program a universe simulator. Cuts down on the amount of calculations you have to do if you can get away with just being a wave of probability most of the time. No need to render something that isn't being used by the simulation.

[@elio7610]

I don't see how there is any difference in rendering, either way, the only part we observe is the interaction, which occurs just as much when the end point is random.

[@prolamer7]

I just hope universe isnt "school" project..

[@bagzhansadvakassov1093]

If you do a lot of math you see a world as math objects. Same for coding.

[@Cyphall]

If this isn't yet another hint that our universe is an highly optimized simulation, then idk what it is

[@whataniSoar]

@@Cyphall it's really more of a hint of how little we know more than anything

[@Juss_Chillin]

This is BY FAR the absolute best explenation video of this whole topic I have ever seen! Insane work!

[@musicalcontessa4275]

Agree!!!!!

[@calicoesblue4703]

Facts💯💯💯

[@shkotzim_bacon]

I wouldn't necessarily consider it the best explanation. He made certain errors regarding the double-slit experiment, and he presented incorrect probabilities for the three-polarizer paradox. I would describe it as a fair overview of various light-related topics, but there is room for improvement

[@christianpulido8360]

​@@calicoesblue4703 Science experiments are models based on assumptions with simplified calculations and left out data. Thank you for your opinions.

[@calicoesblue4703]

@@shkotzim_bacon What was incorrect about the double split experiment???

[@code1017]

I’m not a complete idiot when it comes to this but very far from any advanced college level stuff. So for me personally, you described and animated the double slit experiment in a way that made it easier to completely grasp. So thanks for that! 👏🏼 also I’ve never heard of the experiment with the polar lenses. So amazing to think about and mind blowing! Keep up the good vids 👌

[@michael.forkert]

_Any Speed is obtained by measuring the distance first and dividing it by the time an object took to cover that distance. Therefore it is impossible to have obtained 299 792 458 m / s for the Speed of Light. That speed could only be obtained by predetermine a distance for the segment multiple of 10 (300,000,000 meters for example) A->B to be covered by the object, and after that measuring the amount of time the object has covered the predetermined distance A->B (300.000.000 meters) starting your timing device as the object passes A (zero) and stopping your timing device as the object reaches B (300.000.000 meters). Nobody has ever done that, i.e nobody has predetermined the distance 300.000.000 meters in beforehand to reach the conclusion that the light has covered 299 792 458 meters in one second, is impossible. The Speed of Light is an Invention created by bamboozlers. And if The Speed of Light in fact existed, it wouldn’t make any difference at all._

[@Acoustic-Rabbit-Hole]

Also, be aware that we were taught wrong by the scientific community, which suffered form the pressures of conformity. There is no such thing as a photon. A photon is not a "particle" emitting from the sun. Rather, it is a wave-form measurement of the ether being essentially “magnetized” by the sun. We ultimately perceive warming sunlight as a visual (color), but really, there is no "light" per se; the sun is merely “warming” the etheric fabric of space around it. We are seeing a sort of musical vibration. To some degree, in some SENSE, the ether IS the light. We are eternally and intrinsically bathed IN the light. I talk about the nature of color and music on my uTube channel here, of the same name: The Acoustic Rabbit Hole. God Bless.

[@adrianbik3366]

​@@michael.forkertThe only bamboozler that I can see here is you. Nobody measured the speed of light by letting it travel across a distance and measuring how long that took it. There are many other ways to do it like deducing it from it's wavelength, knowing that it's constant. You're using fancy numbers and weird reasoning to trick people into forgetting their common sense

[@michael.forkert]

@@adrianbik3366 _In 1676, the Danish astronomer Ole Roemer (1644-1710) became the first person to measure the speed of light. Roemer measured the speed of light by timing eclipses of Jupiter's moon Io._ _Even to measure a speed of a wave, it’s conditio sine qua non to have measured the cycle, or the length of the wave first._ _Hz is the physical quantity which measures the speed of a wave, or cycles per second. If you don’t know the wave length first, you cannot obtain its velocity as well._ _Velocity (any velocity) is distance divided by time. If you don’t the have measured the distance first, it’s impossible to determine in what span of time an object has covered an unknown distance._

[@michael.forkert]

@@adrianbik3366 *You're using fancy numbers and weird reasoning to trick people into forgetting their common sense* _Nope, exactly the contrary, I’m using THEIR fancy numbers and weird reasoning to retrieve the common sense, which THEY, the pseudoscientific bamboozlers, have erased from people’s minds._ _If you desire to reason or ponder about fancy numbers and absurd reasoning, I recommend you to start with: The diameter of the the “observable universe” is 93 BILLION light years long._ _To spare your time from doing the math, I’ve translated this distance to kilometers and miles ._ _93 billion light years are 8.7986e+20 km , or if you prefer 8.79 SEPTILLION KILOMETERS. (If you desire to transform that distance to miles, just divide 8.79 septillion kilometers by 1.609)._

[@urath55]

In one of my first lectures in my chemistry studies we learned that everything falls under this wave-particle duality (or quantum probabilities if you want to call it that), but the heavier it gets, the less likely it is to behave like a wave. So in theory, we humans could also walk through two doors at the same time and interfere with ourselves, though to be fair the probability is relatively small (:

[@Arlecchino_Gatto]

I have done that before.

[@timhaldane7588]

Do we know if the probability is actually tied to mass (heaviness)? Or is it particle count? I always assumed the latter (the more particles, the greater the quantum decoherence).

[@GerardMenvussa]

Time to go on a diet...

[@MCDainter]

Yeah lol but dont forget that the wavelength of a human compared to our size is -10^30's so our wavelike propeties are miniscule.

[@Extremebiker0]

​@@timhaldane7588very hard for you to pass through a doorway without having a detectable effect on the surroundings. Footsteps in the carpet, movements in the air, etc. This is the trick the photon is pulling which allows it to pass 2 slits - no measurable effect on its surroundings. Because massive objects have a gravitational effect it gets very difficult to move them around without them having a measurable effect

[@1234kingconan]

It’s probably to save memory. In video games when you don’t look at stuff they render it with less detail or just don’t render it at all. If you quickly turn around sometimes they all ragdoll fall onto the ground, because the game didn’t save their positions and continue to render them. So maybe the universe is saving memory by not rendering anything until it’s observed.

[@jasondashney]

Abut 30 years ago I read a book about the holographic theory of the universe. Same concept. The universe doesn't exist until you perceive it. What's behind you.....isn't, until it's observed.

[@yehor_ivanov]

@@jasondashney the classic buddhistic principle, actually! "if a tree falls.." - U can google the rest)

[@paradiselost9946]

@@jasondashneyso what do blind people experience? and what about blind AND deaf?

[@jasondashney]

@@paradiselost9946 I did say perceive and observe. I didn't say see. Of course I'm being pedantic because if I'm referring to what's behind me, I'm definitely referring to sight, but you're being pedantic as well so I will point out that both perceive and observe are not limited to the visual realm. Observation just means you sensed it. So does perceive.

[@SemenTheSailor]

I’ve always understood the concept of the double slit experiment, but never really understood the implication. When you described observation as an interaction, everything fell into place in my mind. I have never heard it explained like that but it all makes so much more sense now. Thank you for this video.

[@helgevig5134]

Yes, the part about how observing necessarily implies introducing other elements in order to observe (hence having influence), that really makes sense of it to me.

[@YrHopesAnDreams]

Makes me wonder what the nature of an "interaction" is exactly. Is it any time that information is altered, from it being stored in a new place, even as a copy (such as passing information along to another person, or just copy paste) or a slight shift in the sand of a distant planet billions of light years away? Or does there need to be an observer of some variety, and then what defines an observer?

[@erinm9445]

@@YrHopesAnDreams This is one of THE great questions of quantum physics today, and any physicist who can satisfactorily answer it is sure to earn a nobel prize for their work, but for now it is just a mystery. It's known in physics as the measurement problem.

[@BucharestRO]

So can you prove Mt Everest is there if nobody watches it

[@BruceWayne15325]

It sounds like light and water have a lot in common, just on a much smaller scale. I suspect that light, like water, is attracted to pretty much everything, which is why observing it would make a difference. If light photons, like water droplets are not actually an atomic unit, but rather a collection of attracted objects then it can move in a wave, or as long as nothing interferes with it, act like a particle.

[@Fatdog-Dakind]

It's something to do with going through the slit has an effect on the photon somehow creating a harmonic effect. The wave part of the photon seems to react like a 3rd or 5th harmonic that we see in radio waves huh? No slit, no effect right?

[@andrewmueller8803]

I am also curious about the single photon going thru a single slit. I was also thinking of the radio wave double slit experiment. does it act the same?

[@Fatdog-Dakind]

@@andrewmueller8803 Interesting huh? It's probably the same effect! It's like when you mix two frequesncies togther you can make a completely new frequency... the same with light too huh!

[@jasondashney]

My brain has such a hard time imagining "smallest". If it's something, then how can you not cut it in half? I remember first thinking about this when I was about 4 while watching an ant walk. I thought about how tiny it was and then thought about an ant half the size, or that ant cut in half. Then cut it in half. Then cut it in half. I'm very doubtful we've gotten to the bottom of "smallest".

[@BruceWayne15325]

@@jasondashney the simple answer is that we don't know if there is such a thing a smallest or not. Every time that we think we have found the smallest thing possible, we find that there is something smaller yet. We used to think that atoms were the smallest thing, then we discovered subatomic particles. I suppose it depends on how fine the fabric of space time really is. Is it infinitely fine, or is there a super fine, but finite limit to it? Some research has implied that it might be finite, hence the universe is a hologram hypothesis. I don't tend to agree with that hypothesis, but it illustrates the point.

[@katiekawaii]

I've watched approximately three million videos on this topic, and I think this one is the clearest I've seen. You're an excellent storyteller, and you communicate these complex experiments and their findings like a perfectly crafted story. It's brilliant.

[@ChemistTea]

Doubts

[@Trippyricky69]

No Doubt that this is the first one you’ve watched

[@TheDavidlloydjones]

It is nothing of the sort, Katie. It is perfectly routine, with stupid spots. You need to get out more and see competent lecturers.

[@cforchex]

I've watched approximately '3,000,000 videos on this topic' - that's actually funny

[@cewilk00]

The probability is 3 million. It collapses to a smaller, more precise number upon observation. My results concur.😂

[@firstnlastnamethe3rd771]

I always learn something new on your channel, but this episode was especially illuminating.

[@astrumspace]

Ohhhhh

[@maryannedwards5424]

"illuminating" "Ha . . Ha . . Ha" Very good grasshopper . . 🙆💕😻🫂🌹

[@UpperDarbyDetailing]

So how old is your kid?

[@firstnlastnamethe3rd771]

@@UpperDarbyDetailing Yeah, that one sounded like a dad joke to me too.

[@theklaus7436]

One of my favourite shows! I read physics years ago and jumped to music- so now I’m catching up on physics. I listen to almost every single show there is! Amazing to be honest

[@ngaourapahoe]

I went through the tumbler, had chills, my jaw dropped multiple times and I am in awe. This is better than magic.

[@TerribleShmeltingAccident]

For sure, the truth is much stranger than fiction

[@catdeme454]

it is what magic is really and knowing how to manipulate it, direct it............becomes a science. That is why the best sorcerers are scientists.

[@nocantry]

I love an educator who acknowledges the fact that we don't know the full picture. Paradoxically, it makes them more reputable in my eyes.

[@willchoice7681]

no you just like feeling better about being ignorant

[@TheBinaryUniverse]

I prefer one who has more answers

[@DarkmoonUK]

You're the scientific one, the other two comments are immature. No space to learn if you don't acknowledge the gaps. That's where religion comes unstuck.

[@GarthWatkins-th3jt]

Right. Gives us Barabbas, crucify the heretic, gives us the notorious murderer!¡!¡! Crucify the truth! Or, give us an answer as long as it doesn't conflict with our stunted, flawed thinking. Having said that, don't presume to know other people's minds. You could be incorrect. If you weren't there when something happened, did it even happen? Can we rely on ANY information relating to our history? Maybe. Some things more, some less. The very idea that observing an experiment changes the results is, to me, an important answer to a broader question....

[@Rocksite1]

What's paradoxical about that? Here's a quote by Einstein: ""The more I learn, the more I realize how much I don't know." A key part of science is questioning beliefs and foundations. All detours aren't necessarily productive, but the ones that are, can be breakthroughs; and technology doesn't progress without them. Now if science could progress more readily in directions other than favored by tyrannical oligarchs ...

[@roymcroberts8683]

I've seen a bunch of videos about this and I can honestly say this one made it the easiest to understand I've ever seen. Great job guys.

[@dlseller]

Hi Alex. I just wanted to say how much I enjoy the enthusiasm you show in your videos. You enthusiasm comes through so clearly I can almost year you smile when talk. Thanks!

[@KiraandtheSurvivalPod]

This is one of the best KZbin videos I've ever seen. Really interesting content. Great voice. Great teaching. It's nice and calm. I get overstimulated on other KZbin videos and this one is perfect. Thank you!

[@winningjubbly9712]

If I was a lonely man travelling in my lonely spaceship with only a cat for company, I'd want my ship's AI to have this narrator's voice. It's such a friendly voice I honestly think it would stave off depression. Everything would always be awesome and excellent!

[@SteveLevy-ld7hl]

the amount of tiMes i have heard dis sonG..EyE had a dream🕉WoW dis is live...whAt w00d you Say..2 your Selfish selF....if EyE Could tiMe...888 inFinty with da ...tiMe traVller spAce tiMe continue ATAR🕉🕉🕉 aNd thEn my b00k...

[@jaxbronson9734]

How do we know he’s not an AI and you’re not a lonely man in a lonely spaceship with only a cat for company and I’m the voice of that cat communicating with you telepathically through this simulation?

[@FolkLoreSaint]

😂

[@kenkioqqo]

Someone's watched too much Sci-Fi 😅.

[@Smedley1947]

Open the pod bay door, HAL. I'm sorry, Dave , but I can't do that.

[@Kwauhn.]

I love your cosmology videos, but I'm especially loving your videos that branch out into other areas of physics!

[@astrumspace]

Thank you! I do try and keep it space related still. If we as viewers don't really understand light, then we won't understand the cosmos.

[@1112viggo]

The great thing about physics is that everything branches out into everything else. When it seem that it doesn't, that´s a clue we have something new to discover about reality.

[@Deltexterity]

@@astrumspace for what it's worth, i really liked this change of pace and would love to see more of it!

[@xybersurfer]

great explanation. just the right amount of detail and i like how you went into the history

[@yoursoulisforever]

Back in the 90s I remember doing the double slit experiment and also an experiment with a candle and pencil but I'll have to Google it now to remember it better. It had something to do with an old theory about boundary conditions between light and shadow if I remember correctly. Anyway, it was interesting.

[@larrywalsh9939]

Very illuminating, no pun intended. Before I watched this video, I didn't know much about light - now, I still don't know much about light but at least I have a clearer picture of the sheer depths of my lack of understanding.

[@BluephsBlog]

I think the reason particles behave differently when looked at compared to when not is that we are "looking" at captured moments of time while reality doesn't exist in separate moments.

[@sunnyboy4553]

Thank you!!!

[@asmemeas]

Yeah in a sense all possible combinations exist its just we only get to observe and experience one path but at the same time we're almost woven into every other possible outcome. I guess that's why I love the many worlds theory. Just thinking about how it could be possible we exist outside ourselves and are constantly experiencing ever moment that's ever happened simultaneously is just such a fun mind tickle. Now I might just be high talking out my ass and rambling but these type of thoughts are so interesting to explore.

[@Akiramaster]

measured, not looked at. You interfere/interact with the wave. It's not magic...

[@ElyziumPrime]

We just live in a simulation lol

[@johnramirez5032]

I think your really close to the truth. Reality is.....? The past is but a record. The future is but an idea or dream. Reality is creation in motion. I have a saying. We dream the life we live. Its odd to most people unless they think like i do. In any case does it matter ? Do today what you will be happy with tomorrow. Its odd ....the past. It doesn't exist yet we place so much value in it.

[@AJ___USA]

I think that the act of measuring light with our modern equipment is affecting it and causing some type of atomic reaction I believe that when the single particle went through the double slit experiment it reacted like a wave interference because our measurement equipment was interfering with that particle going through the experiment

[@quantisedspace7047]

Yes, this to me is quite obvious: you can't measure something without changing it in some way and there must come a limit that when measuring it, it causes it to be destroyed altogether. It's not at an 'atomic' level, though; it's more subtle than than, bit your basic observation that observation will necessarily change what is being observed is correct.

[@kyburton]

I love the smile in your voice as you question the certainty of reality at the end. Some people feel afraid of uncertainty, but I don't think there's any reason to be! Things have worked out so far, haven't they? We're experiencing something, after all. I like going through life with a curious smile.

[@justinmayhew6848]

I have never seen a better explanation of the things you discussed in the video and i've seen a fair number. I started watching for your videos on space but if the videos are this good I will watch your videos on any topic!

[@ggtt2547]

Excellent video. Short, to the point, simple and really complicated all in the same time. Congratulations.

[@musicalcontessa4275]

I love this! Love the study of light diffraction. I have a lamp in one room of my house and in a completely separate, different room, all the way towards the back, there is a perfect reflection of the entire lamp----which exists in a completely different room with an entire dark wall separating the two rooms, yet the reflection of the light somehow bends all the way around the entire wall, into the other room, all the way to the back door. When standing in the back of the other room on the other side of the house, it is impossible to see that lamp at all in the other room, in the other part of the house.

[@kennethd.lehrman5080]

Cool

[@davidfraser6083]

Light reflects off of surfaces.

[@musicalcontessa4275]

The cool part is, if I block the light and allow just a crack of light, somehow the diffused double reflection of that lamp still bends around the door and wall and travels its way all the way to the back of the house to still show the dual (two lamp) reflections of the lamp.

[@thepuma2012]

@@musicalcontessa4275 that s funny, show it on video (or photo)

[@ingridgilbert4917]

I would like to see it too, very interesting. @@musicalcontessa4275

[@jasondashney]

This might be the best science video I've ever seen, and believe me I've seen my share. Some things clicked in this video I've never been able to fully grasp before. I can't accept what's until I understand the why's and this video snapped some into place and I'm so grateful for that.

[@laurapope3685]

Thank you so much for putting out another great video! I really enjoyed learning from it and I can't wait for the next one!

[@jamesdonalfaulkner]

Likewise - or should I say "lightwise"?

[@OctagonalSquare]

I love that the polarized lens rotation example can be done at home and you can visually see the results. Literally just need 2 pairs of 3D glasses. The double slit and such can kinda be done, but normal people don’t have the ability to observe photons to make it exhibit a discrete value.

[@jeremiahlethoba8254]

Also, the 3 polarizer paradox is in effect on you phone's LCD screen now. The liquid crystal (LC) is sandwiched between 2 linear polarizers and acts like the 3rd polarizer in the middle in the 3PP example (except it functions as billions of polarizers sandwiched between 2 polirizing filters)...the purpose of the LC is to vary the intensity of the 3 RGB LED's for pixels in at least 256 ways to produce images in all digital devices 😊

[@OctagonalSquare]

@@jeremiahlethoba8254 yeah but you can’t personally interact with it in a way you can get to see it work

[@misterlyle.]

Regular sunglasses that are polarized will behave this way. Whenever I buy new sunglasses, this is how I verify at the store they are actually polarized and not just tinted. So that means the three lens activity should also work.

[@quantisedspace7047]

Can't see what's so surprising about the three polarising filters: Everybody is taking the word 'filter' literally. A polariser lets light through by twisting it if the incoming is within its acceptable range. If you try to stuff a piece of card through a horizontal slot and the card is say 45 degrees, what's going to happen? Half the time, the act of insertion will realign the card and half the time it'll just get crumpled. Try to put it through at 90 degrees and it won't go at all. Put two opposing polarisers in series and the first will twist any incoming out of range of acceptance by the second. Interpose a third polariser between the two, and some of the light will get twisted into that plane, which will then be in the acceptance range for the final polariser. This isn't mysterious; it's exactly what I'd expect to happen. It would help if people stoped referring to polarisers as 'filters': they twist rather than block.

[@solo-ion3633]

This is the best explanation of the 2-slit problem I've seen.

[@alejandrorincon5649]

Hands down!

[@Onion_of_Ultimate_Concern]

​@@alejandrorincon5649hands up!!!....this is a robbery!

[@quantisedspace7047]

It is no more helpful than any other. They're all good, but none explains two things: 1) Why do we assume a photon must go through one (let alone both) of the slits at all ? 2) Why are we surprised that adding a photon detector changes the outcome ?

[@TragoudistrosMPH]

This was so well done. Most people don't define "observed" and your descriptions of the single photons were excellent!!! So much clicked that I didn't understand, before! Thanks!!

[@AlexisOmnis]

I agree; it's important to always assume you're telling someone who doesn't know what certain terms mean. I didn't study this but have taught myself certain theories & concepts but when something important isn't properly explained you hit a wall. Like observation, in this sense, is when something has been detected by some form of sensor.

[@xybersurfer]

yeah totally. these videos rarely explain what "observed" means. a different video cleared up the confusion for me in the past, but i still recognize the value in explaining it

[@quantisedspace7047]

OK, I'll concede that but we need a much more rigorous treatment of what we mean by 'observed'

[@XD152awesomeness]

I’ve heard the polarizing lens experiment explained before, but this video did it so much better

[@DanielVerberne]

I've heard some scientists don't actually support that experiment. It's proven to be quite ... polarizing 😁

[@milenamilena4495]

the only benefit of the polarizing experiment is to gain understanding for how multilateral and multichannel and diversely vibrating a natural light is. It's the package not the parts

[@floffycatto6475]

This makes me think of a Slo Mo Guys episode when they went to a lab where scientists were using the world's fastest cameras to capture light in movement.

[@quantisedspace7047]

How pray do they do that ? To see a photon, you have to be looking along its path, thus blocking it. You can't see light 'in transit' because that would involve a sideways view, and you see nothing if looking at a photon from the side wrt ita dirn of travel.

[@virginiaalfaro6186]

The visuals were really great and helped me follow the concepts. Thanks for an intriguing video

[@pbjandahighfive]

I genuinely feel like the issues with quantum probability lends a lot of credence to the idea that we're living within a simulation of some sort and we are part of some sort of massively complex AI system. It would explain the Fermi Paradox, it would explain why at quantum scales everything seems to operate in yes/no 1/0 absolutes, it aligns with probability, it would explain why there is an absolute size limit and absolute smallest unit of time (planck limits) instead being infinitely divisible, ect.

[@sodiumvapor13]

I have the exact same thought when learning about the quantum universe. In that same though process, think about how strange it is that we live in a reality where we can only ever be concious for a set amount of time... and if we push that limit (by not sleeping) we go crazy. We always have to "log off" every night... like maybe we're just players in a game?

[@JPA65]

@@sodiumvapor13I hope I’m filthy rich in my ‘real’ life

[@fredfarquar8301]

I wish you had mentioned the experiment performed with light by a graduate student. He realized that, while the double slit test with electrons showed that particles also can behave as waves, the same test of waves had not been done. So he did it. He set up a laser, sent the beam through a beam-splitter, then each of those beams through beam-splitters, and sent both pairs of beams into two interferometers, setting up interference patterns in each. Then he blocked ONE of the four final beams….and BOTH interference patterns disappeared! This proved both quantum entanglement (if some of the photons were disallowed to interact as waves, ALL the photons from the same source could not interact as waves!), and that, while matter cannot move at the speed of light or faster, information CAN! And also casts a shadow on the notion of cause and effect!

[@fonesrphunny7242]

Is there a link to the source or video?

[@fredfarquar8301]

@@fonesrphunny7242 I used to have the citation, but doubt I could locate it now. The experiment was performed and reported in 1991 or 1992, and was reported in Physics Review or Physics Letters or something like that. Google it, maybe?

[@Suburp212]

Wow. This is the best video on this effect, I habe ever seen. Well done. High production quality. Well done, Alex.

[@kenhutley971]

Bravo... and Thank You for this valuable clarification. Much appreciated!

[@kdud2799]

Thanks for a very beautiful, and simple illustration of complex phenomena, especially the double slit experiment. I've never seen or heard it illustrated in such a simple and straightforward way. I think another question to add is, Of all the probabilistic options available for light to assume in space, what makes it take on the form it does when observed? That is in the double slit experiment, what makes the waves condense to the right slit and pass through it as a particle instead of the left under observation and vice versa, when it has the capability to pass through both when not observed?

[@SchemeTintFocus]

I love these modestly forward science videos. Pursue understanding as it evolves, so do we

[@tjwoosta]

I love the discussions in the comments these days. I've seen videos about the double slit experiment and quantum physics for many years, but even just a few years ago the entire comment section would have been like a bunch 6th graders calling each other names and referencing biblical quotes. We seem to be approaching a point where we can actually discuss things without dogma.

[@matthewverde3390]

Loved this video. Your teaching style is unmatched! TY

[@whooshmeifgay2593]

What always confused me about the double slit experiment was that: when we are identifying which slit the light went through, we have to somehow interact with the light to detect it, thus influencing the result on both sides (the expected result, not the interference patter) Having said that, would that mean only observing 1 slit (did it go through, if yes then we acknowledge that we introduced a single variable in measurement), how then would this affect the results. Like 1 side being a single line, the other side being an interference pattern? Idk what I’m saying but my curiosity made me comment.

[@egglion7931]

If one slit was being observed and one wasn’t, then it would make a 50/50 mix of the two patterns. Any photon which decided to go through the observed one (which should be 50%) makes dots and one that goes through the unobserved slit will make the interference pattern. It will be both.

[@ovonijemojeime]

​@egglion7931 what you've introduced, to me seems like the idea of the "range" of the detector. I liken it to a speed camera for cars, a car is caught speeding once it enters a space on the road where it can be determined that its speeding. But that car is visible to the camera before it enters that space so it's still interacting with the camera even before its caught speeding. Maybe photons are so sensitive that the "detector" interacts with them regardless of whether or not the detector is looking to measure it at that space. However I'm not sold on the idea of photons, because I don't think that a photon has ever been the input or output of a scientific experiment. That "photon gun" is very suspect to me.

[@quantisedspace7047]

​@@egglion7931and what happens to the photons that go through neither slot ? How do you justify this 50/50 ratio ?

[@quantisedspace7047]

​@@ovonijemojeimeYes, this is correct. Photons are indeed that sensitive..You can not measure /anything/ without changing that anything. That's obvious and you don't need QM for that. A photon is so sensitive that you can only detect it by reducing its energy (perhaps to zero). Ergo, any measurement of a photon will, of necessity /change/ that photon. Why on earth do people see this as a problem ? You can't measure voltage or current without changing the V/I in some way, you cannot test a tissue sample without applying some destructive reagent to that sample. Why is it seen as 'magic' that observing a photon would change it's behaviou That's exactly what I would expect.

[@egglion7931]

@@quantisedspace7047 a photon that goes through neither slot will not be detected and will not leave any mark, it has no impact on the patterns that the photons that do go through make

[@adamb8317]

Crazy how all quantum particles behave in this probabilistic fashion. However, if you add up just a few probabilities the mathematics become practically absolute.

[@markdavid7013]

There has to be deeper understanding of universe at it's fundamental level that we simply don't posses..

[@NPCSpotter]

That pretty much goes without saying

[@bretthanes337]

Great video! Strangely, first time I’ve heard of the triple polarizer problem. Very cool. 🤓

[@alexanderhugestrand]

The double slit experiment is easy to explain in classical terms. Entanglement is also possible to explain vaguely using some hand waving arguments. But then there's ghost imaging and the delayed choice experiment that messes it up a bit. What they all seem to have in common is a faster than light mechanism (maybe even immediate) that senses the environment. A "probability wave" could in fact be a wave of space itself. There is no space where there is no probability, as far as the particle is concerned.

[@kawosdhdos]

Great video! The visuals made it simple to understand!

[@nilsp9426]

I think light is a great example of an epistemiological problem with mathematical models of nature. We observe an attribute of an object. Then we theorize about it and make a model. If the model predicts a lot of outcomes of various experiments, we are happy to say that it is a very good representation of the object. But there is no logical way to say that the nature of the object actually is what we describe in the model, because empirical research does not identify objects, it just describes them. Logically and epistemiologically it is actually increadibly hard to fully support statements of the form "X is Y", such as "Light is a wave". But we can easily say "If light were a wave, it would show the properties we observe."

[@silentwitness9255]

Do you mean epistemological; as in words and language? Using one phenomenon to represent another moves us into the symbolic. Science and philosophy kiss again.

[@stainsmelly]

No one takes into account the thickness of the partition with slits. I think they can't all go through at a perfectly perpendicular angle . And a % actually ricochet off the slits frame opening. Because they are spherical particals . Like shooting a million tiny balls down a hall way. How many will interact with the walls and redirect their trajectory... a %

[@Highlander515]

Great video I thoroughly enjoyed watching and learned from. One suggestion I have is at 4:42, some explanation of intensity vs frequency would help audience understand their differences and the resulting effects of changing them.

[@MrTwisted003]

I agree, I wondered how many would understand the difference and what they entailed. For a sec I even thought I reversed them until he finished his sentence.

[@MrTwisted003]

@@BobbyT-yj1cw yea, i know the difference. Just as i thought about it i wondered if others did too. There was a time i didn't. Just suggested more detail from good vids like this gets more people the correct education, something 99.9% of the internet lacks.

[@phumgwatenagala6606]

Intensity is how many photons per unit time - frequency is the energy of each photon. So you can send low intensity light composed of high-frequency photons

[@Antonio-ow7if]

The best explanation of the fundamentals of light I have ever seen. Thanks!

[@treschlet]

oh hey, this is the most succinct and easy to understand explanation of wave function collapse that I've seen, and I understand it way better now

[@primiq]

Only your videos make me want to take the whiteboard out and start thinking outside the box. Getting past our paradigms is so difficult :( I cant wait to know more about the energy systems that we are part of! Thank you!

[@Hendrik_F]

Thank you for clarifying what is meant with "Observation". There is a common misconception, that the behaviour of quantum partices depends on a sentient observer. But in reality, an observation can be any kind of interaction with a particle.

[@JeffCaplan313]

Aren't interactions happening all the time? When is an interaction not happening? They even happen within/around vacuums. This just seems like saying the bigger the interaction, the bigger the response and how is that not Newtonian?

[@Hendrik_F]

@@JeffCaplan313 That's a good point actually (your first one). I can't claim to completely grasp the theory, but I think the basic idea is that you can treat any subsystem that is sufficiently closed of from the outer world as one "quantum system", for which the wave-behaviour applies (like for example a bunch of atoms suspended in a magnetic field in a vacuum. The light in the double slit experiment also has no interaction between its emission and the detection). Then, on a small enough timescale, no interactions with the outside world occur, until one makes a measurement and the entire system collapses into one definitive state. So yes, interactions happen all the time, but when multiple particles nly interact with each other, you can treat the whole bunch as "one" thing. Like Schrödingers Cat, where the cat is (in principle) part of the subsystem. I dont't really get what you mean with your second statement, sorry. Newtonian principles seem like a whole different thing to me.

[@j3ffn4v4rr0]

​@@JeffCaplan313 I think you have in mind Newton's Third Law, "for every action, there's an equal and opposite reaction". That's a good point, but actually these are 2 very different cases. First...no, in fact interactions very often are NOT happening...e.g., a photon leaving a light bulb is not interacting with anything at all, until it hits something that it illuminates. A star which you view in the sky, has photons which literally avoided interacting with anything for millions of years...until the precise moment it interacts with your retina. To bring it back to Newton: the quantum nature of particles means interactions happen in fixed degrees only....this is the (a) difference which separates quantum physics from Newtonian physics. Particles are not tiny balls bouncing into each other...they are tiny fluctuations of energy fields (waves) traveling through space, which cause changes of a precise quantity (a "quantum") when they touch other similar fluctuations of energy fields. (The same, or other, fields) This quantized change is what makes the wave now look like a particle. ANY interaction of any 2 objects in the universe is ultimately particles (aka, tiny fluctuations of energy) interacting with each other, in this quantized manner.

[@engineerahmed7248]

We can discern a correlation: the smaller the wavelength, more pronounced particle-like behaviour & the greater the mass carried by light. Upon observation, the observer photon fuses with the original photon, augmenting its mass. Consequently, the resulting, more massive photon tends to manifest itself more as a particle, mirroring the behaviour observed when gamma rays fuse into particles like electrons. This deduction offers an elegant explanation for the intricacies of mass-particle duality without invoking Einstein's theories.

[@PaulTancre]

This is fascinating…I want to know more! Great content

[@thatjeff7550]

Thanks for your concise explanation regarding the double slit experiment. I have heard this experiment described to me on several occasions throughout different times of my life and every time I heard the lecture, it just made me more confused. The last time was, "How can an observer affect the path of a photon, especially when the observer is mechanical?" I hadn't thought of the observer (or detector, I should say) affecting the photon with its own particles in order to detect it. You solved a very old issue for me.

[@Rose_Harmonic]

I remember some quantum mysticism people talking about how the act of perceiving things affects them and I'm sitting there thinking about how the act of observing requires us to bang on the subject with other particles.

[@Oblivionburn]

I wish I could like this comment thousands of times so it's the first one everyone sees for this video, and then copy it to every other video about the double-slit experiment and quantum mechanics because the perpetuation of this misconception about observation needs to end. I'm tired of having to explain to people that "observation" in scientific terms is analogous to taking measurements with an instrument like a laser, which is literally what the original experiment used for measurement/observation... of course shooting something with a laser is going to make it behave differently than when it's not being shot with a laser. This would be a no-brainer for most people if they were told the truth instead of the fantasy.

[@milenamilena4495]

is it the intent (of the mind) setting the wave-particle behavior? and why scientists influence results of their own research? what is the human mind and how it interacts (or bends) light?

[@botezsimp5808]

My intuition always figured it was something like this. Measuring something requires contact of some sort.

[@drewg2403]

This also the reason for the Heisenberg Uncertainy Principle. When trying to measure positions or velocities on a sub atomic scale, we must measure things through some type of physical interaction, usually bouncing photons or other particles off at certain angles and then detecting them. But doing this imparts energy onto what is being measured, altering the outcome of the measurement.

[@jeffclarkofclarklesparkle3103]

This paradox always makes me wonder what the effect is on galaxies very far away when we look at them with telescopes, compared to the ones we can not see or haven't observed yet. Does our looking at them change them somehow? Have others observed our galaxy in the past and changed things here? So many questions arise from this conundrum it makes my brain tingle

[@ammi7462]

If you don't exchange information with those who observed the universe/galaxy in the past, it will not matter, as they will be a part of the probabilistic wave function. It is truly strange, and also makes you question time. A wave is bound by time: For waves to make interference patterns (destructive or constructive), it needs to happen at a certain place and at a certain time. But when we shoot single particles one at a time, and it still makes an interference pattern, it is as if those single particles interferred with eachother backwards and forward in time - so in that sense - the quantum world is timeless. Everything is somehow happening all at once, but we who observe it see it as probabilites. Now, it seems the wave function does not callapse unless something "conscious" is observing it, either directly or indirectly with sensors or an array of sensors. In another experiment which has been conducted and reproduced several times, a quamtum dice which gave either 1 or 0 (50/50 probability) would be affected if the observer whished for either 1's or 0's...so in those cases, the observerer was creating and directing reality, most mind fucking.

[@keichannnn]

the single photon experiment, all these youtube videos only has animation and no proof

[@KibyNykraft]

The newest Webb images from the better telescope than the Hubble one shows very clearly that the galaxies far away are orbiting a centre. You can see that from their shapes and how they are stacked up formationwise. They look like they are boats in an eddy like a whirlpool of water. This is a proof of a multiverse, that on all levels there are entities orbiting a centre of some form. (And a big problem for the big bang concept as a "start of all from a nothing, which to me sounds mostly like christian doctines /creationist cosmology)

[@KibyNykraft]

@@keichannnn there are many pseudoscience videos posting as science with no skeptical evaluation behind the thinking, sadly... Each traveller has its own experience perspective but acts physically with whatever other physical regardless of the senses. Stand ahead of a bus in high speed. Have all your senses inactivated as much as possible. No change, the bus will hit exactly the same way. Your observation has no effect on the outside world. It exists 100 percent independent of your senses. Light are just massless particles, but the bus is made up of particles. In principle no difference here.

[@FensterwischerX]

You can not observe photons at their location in other galaxies and therefore not change anything by observing. You see what already happened since the photon needs time to move towards you.

[@johnston.scott64]

We'll have to admit, as a lifelong scientist, this particular idea that the concept of harmonics can interfere with energy like light on a quantum level never occur to me before. It's even though as soon as I observe it in the video, that's exactly what I thought. And when they show the images of the guitar I was like damn that's exactly what happens when I hear sound. I have to put in here that I've been a musician since I was seven. But the video gave me a particularly new insight that I never thought of before. I've always thought, never bothered to indulge myself into an experiment on it that light acts like every other type of energy that I've ever seen expressed. It is unpredictable and always reacts in the quantum level. No matter what type of energy we understand it always reacts differently at the quantum level but I never thought to myself that it could interact with its own self at the quantum level. In other words like in the video two guitar strings are being played they're moving in three dimensional producing a sound that vibrates the air around it. Now I understand that obviously the air that vibrates around it definitely affects the sound that's emitting from the original source, the guitar string. I've lived that and understood that for years. But I never thought that the concept of harmonics, which I'm saying is the energy that surrounds concepts of light, would actually have an effect on life because it's such a powerful and overpowering energy source compared to sound. And that's when I realized that what is actually happening is what he explains in the video. Beyond the concept of we watch something and we lose observance and we cannot observe a point of any particular subatomic particle or predict ot and it will change it's behavior simply by observing it, I realized for the first time that light itself is interfering with itself. Much in the way that sounds from two different guitar strings next to each other even if they're tuned to the same pitch, will interfere with the sound of the strings themselves. For me at least it gave me A much deeper and simpler understanding of the concept of the way light behaves. I'm not saying I have the answer of course not, I'm just a really smart guy I'm not a physicist But I have to openly admit, being a scientific skeptic, this is a really interesting concept! And maybe someday I'll write a eureka paper on it! Or being up at 4:00 in the morning I'll probably forget it by 9:00. 😁🤣😂😁

[@petergriffin383]

Wow this was incredibly well done, thank you.. excellent content creator

[@Hi_Im_Akward]

Honestly I think we are observing some kind of quirk of another dimension that we can never directly observe because we live and observe in a 3D plain. The probabilities are probably on the right track but I think there is more to it that we just can't observe or measure. So when we try thats why it collapses. It doesn't actually collapse its more so that we are capturing a snapshot instance of that other dimension.

[@milenamilena4495]

yes quantum probabilities, oops - superposition collapse ocurs when we make a choice, somehow we are participants

[@pbowes5]

Best theory I’ve heard on this is that this is a logical and clear sign that the universe is designed. You can call it Creative Design or a Simulation but clearly something in the code is programmed to care whether humans observe. If you were to design a world there wouldn’t be any need to constantly keep the entire universe loaded. Like a video game, you could save almost infinite memory and energy by only loading aspects when they are observed.

[@misterbonzoid5623]

Or our models aren't accurate enough to explain such paradoxes.

[@pbowes5]

@@misterbonzoid5623 the studies confirming the observation effect is clearly telling us something. Short of God coming down from the clouds this is a pretty big clue

[@jonb4020]

Ths is the clearest video on this subject that I have watched. Thank you and well done! What an amazing, wonderful and awe-inspiring world we live in! 😀😀

[@marklaureyns5574]

This was great. The best explanation I have seen. Thank you

[@ovoj]

An insight I got was that at the most fundamental layer of reality we know of, particles can't tell if don't care if an "observer" is human or machine

[@f0xygem]

Ever since Webb went up, I have been wondering about what happens to photons when they finally hit a target. When they can no longer remain photons, what do they turn into? Do they reliably turn into the same particles or subatomic particles all the time, or are there different configurations? And it just occurred to me that light traveling without hitting a target would travel Infinitely; could that photon accelerate as the rest of the universe does, even if very slightly, in a way that would be very difficult to measure? I would like to share a funny story with you. When my son was a toddler I got a series of science tapes from school district: photosynthesis, the Krebs cycle, and wave-particle duality. A few years later my son saw me play one of these tapes again, and he exclaimed, "Oh, my baby cartoons!" 😅

[@FensterwischerX]

When photons hit a target their energy is transfered to the target. They actually "hit" it like a mass and can even move objects. I don't think the photon turns into anything since it is only moving energy. Fun fact: Everything moves at its speed for ever unless a force changes the velocity. Not only light. Light moves with the speed of light "c". That does not make it harder to measure.

[@nmarbletoe8210]

baby cartoons! nice i think Fenst. is right, when the photon hits it can simply add to the internal energy of the material it hits, e.g., it could heat up an asteroid slightly the photon traveling infinitely would always go the same speed relative to things it passes, but compared to the light bulb where it started it will go faster and faster due to expansion

[@kenkioqqo]

This video is so calming and relaxing. I love this channel.

[@huwpickrell1209]

That orientation sndpping explanation is very clear to me txs

[@sebastianjovancic9814]

My tip to anyone puzzled by the duality: don't be concerned with it, it's a semantic trap. There's no truly satisfying definition of a particle, it just "feels" more intuitive to us, while we have a very well defined meaning of what a wave is, so if you take something specific and try to square it with something vague you're just asking for generations of confusion. If I would try to square it the best I could, the best definition of a particle I have heard is Wigners defintion, which roughly says "A particle is at a minimum an irreducible representation of the Poincaré group". If you're not familiar with group theory, that definition is probably a load of gobbledegook and nothing of what I'm about to say is really going to feel any better. But suffice to say, nothing in that definition really precludes any wavelike behaviour of a particle, in fact the algebraic structure of the Poincaré group is specifically a group for a relativistic field theory! In less gobbledygooky terms, the best way of understanding what a particle is, is by using fields within which waves (perturbations of the field) propagate! Even more specifically, particles are all the unique ways this field can be changed while preserving the laws of physics. All waves are carried by some kind of (quasi)particle, every particle propagates by means of some wave (assuming you believe in quantum mechanics). Any duality is a red herring, just like the mind-body duality!

[@milenamilena4495]

agree, and the way you describe it - doesn't it apply to society, same wave movements defines by a quasi particle (a leader), on every scale same process?

[@fred-bevhogendorn8023]

When you understand that light is invisible until it meets an object it explains a lot of properties and the two slit experiments is also understood. Phase shifting from forward motion to multi directional motion upon disturbance is a fascinating effect.

[@barkvarkie_fpv8623]

My mind is failing me here .... What I cannot understand due to lack of knowledge, is how can it be said that a camera (or sensor) observing a photon interacts with that photon? To use your statement above, what "object" does the photon in "thin air" (i.e. outside the camera) meet making it visible to the camera sensor? I am thinking about this like a drop of water (photon) falling through space (like in a vacuum tube) and the image of it (not the drop itself) being captured by the sensor outside that tube. The drop is not being acted upon by the camera .... I am making myself dizzy here, sorry.

[@simjam1980]

It 'appears' invisible because, from the light's perspective, it is moving instantaneously...that is, no time passes.

[@joesmith-gf9lg]

@@barkvarkie_fpv8623 They communicate with each other and thus influence each other. Each is a part of the other's "local" reality. Local meaning they are in each other's realm of influence in some manner. At the level of a photon, nearly anything and everything will influence it. Absolutes are matters of relativity. If anything was in a truly absolute state, it would cease to exist to anything else. If light were truly constant, in any sense, it would cease to exist.

[@ats8742]

this gives me another concept to play around my head.. nice thinking.

[@ats8742]

And I think scientists are misled by thinking they can fire a single photon thru the slit? The method of the experiment here should be questioned to avoid confusing and inconclusive results. How can they be so sure that they are firing a SINGLE photon when in the first place they are not very sure of the nature of light itself? Think about it.

[@kmyase1]

Cool! Having more filter allowing light to pass through suggests that light particles are interacting with the filter and changing its polarization! (Focusing effect) just like a bullet ricochet of a wall changing its trajectory and changing the other bullets near it in a chain reaction! I would say light is a particle but in bulk, it appears as a wave like pattern to our eyes/ detectors!

[@kmyase1]

Your light sources is like a gazillion rifles firing continuously and bullets are spiralling out wards bouncing off of each other as they spiralling into bigger radius!

[@KoushaTalebian]

I wish they stopped saying “light knows when it’s being watched”. No. When you observe a quanta particle (and observing means sending some form of energy to detect it) that observation energy collapses the wave function to whatever you measured and that starts a new wave function. So in the double slit experiment, when you measure which hole the light is at, it collapses it to either hole, and now it’s a new wave function that is starting from the slit, not the original light source

[@anorangutan511]

Your last video has had me thinking about light for a month... So glad you did a follow up. I really wonder if light is faster than causality, but we can't measure it's true speed.

[@evnor]

Light can't be faster than causality. Light itself is an effect, so causality can't be slower. Whether causality is faster than light through for instance tunneling is disputed

[@anorangutan511]

@@evnor I probably didn't phrase my thought correctly. I'm wondering if light could faster than 299 million m/s, but we can only perceive it as travelling that fast due to relativity.

[@akgonen60]

@@anorangutan511 with nothing in its way in a vaccum it travels 186,000 MILES PER SECOND THIS SEEMS TO BE THE SPEED LIMIT OF THE UNIVERSE IT IS SUJJESTED THRU QUANTUM ENTANGLEMENT that information travels faster then light when particles are entangled

[@milenamilena4495]

light is not traveling at one speed (sorry Einstein) and Steven Hawkins has proven this, therefore relativity is involved relating to human senses and capabilities

[@duprie37]

It's so incredibly cool that I can actually see all the weirdness of quantum mechanics at work in my bedroom with just a couple of polarised sunglasses.

[@ddeevviiaanntt]

great explanation. thanks for making this.

[@RoboticusMusic]

If the wave of light is continuous time but interactions (measurements) happen in discrete time perhaps the harmonics form due to the intervals at which light or other particles can be sampled (their particles). If you have an analog clock the seconds hand could be anywhere, but if you can only sample it at 11 and 1 o'clock and you can't see anything else about the clock you might come to some strange conclusions about what clocks might really be.

[@br3nto]

8:14 how do you both detect a photon, but also let it pass through slit unobstructed? Maybe the interference went away because the system changed, rather than it being observed? Also I’ve never seen this demonstrated in practice. Only ever animations… can you link to a vid showing the interference going away in real life?

[@brunoborma]

If they still didn't know if a photon was really a particle or a discrete wave-like stuff, how did they know they were shooting "one" at a time ?

[@dazzassti]

Because when light is received at the point of mass then the wave function collapses to be a single photon (think discrete energy value). If you attenuate the light (filter) to the point where there’s no light then you’re at single photon intensity. That’s without going any deeper. I’ve been at this years and still it’s insane. Only recently I discovered a new take on this by a YT channel Huygens optics, I’ve been trying to figure out how long a photon is and so had he. Basically photons in flight are everywhere until they collapse.

[@tykemorris]

They dial down the intensity until it flickers. The flicker indicates quantum packets of light energy alternating with empty space. They have a single photon. Dialing down further only adds longer periods of no light with exactly similar photons. Remember, when they have a detector at one of the slits, it does not interfere with itself or behave like a wave. So why would it act like a single point if it was a wave of multiple photons?

[@kingcosworth2643]

I agree, how do they know. If it is just attenuation, are the sending a single 'photon' or are they sending a single cycle of light, like pulsing a speaker.

[@kingcosworth2643]

@@tykemorris Maybe it is just a single cycle of light, there can be no interference if there is no other waves to interfere with. A 360degree cycle will not interfere with any other waves, but it can be confusing (such as these experiments end up) if there are reflections or impedance issues because even if you only send a 360deg cycle, reflections will be created at which point interference can occur even from a single pulse.

[@johnramirez5032]

​@@dazzasstiperhaps light is a spiral and not a wave? It wierd to think its both until observed. Makes no sense. Everthing is energy i hear. I also hear everything is data so is light smart data. Light can carry information. Does everything come from light? Perhaps light is God. I hear god is everywhere all the time. So what is esp? A collection of data. When we see things in our head do we use light? Energy? We dont seem to know alot when it comes to spooky action . Mabe thats a good thing. We might get bored if we knew it all. What is our sole made of ? If you believe we have a sole im guessing its intellegent light.

[@MillillioN]

I figured out a hypothesis years ago in my hi-nerd years that no one has debunked. I cannot explain it without first laying down an elemental understanding of time, gravity, tiny pockets/particles that we cannot access that light can, points of origin and implications of orders of scale from the perspective of my hypothesis. When you assume that we are anywhere from a millillion to a googolplex of years into existence you will find many more hypothesis to work with. When you assume that we can never detect the smallest or biggest matter in existence you unlock more possibilities. Also, there is a high probability that matter behaves differently over spans of distance that we cannot fathom, if we could zoom out and identify qualities in different patches of space you may well see the ultimate waves... or maybe that would be nothing in the grand scheme of things. Parallel universes, 2D data storage in blackholes and travelling back in time is nonsense as far as I can tell. I gave up thinking about it in favour of a healthier mind as it takes a lot to get new ideas considered, especially when it unifies several areas of science with further implications. I never liked people saying that photons are impacted by being viewed as it sounds mystical instead of logical. The same goes for saying it's probability, although I have a bias and understand that conclusions have yet to be drawn.

[@johnthetireman]

I'm surprised after watching this at the concepts going around. I need to delve into this more as I have many questions.

[@memodump]

The thing is, we try to visualize light interacting with electrons or other particles, and thus we imagine light as a particle too. In reality though, these "particles" are actually waves too, but it is way harder to visualize it that way. Everything about quantum particles screams they are not some pebbles and can only be visualized this way out of convenience. This approach has its limits, and we are now at the point where it does not work anymore.

[@milenamilena4495]

agree, not some pebbles about the "particles". How about humans, why are we pebbles and not one (or many) waves, why as humans we behave like particles rather than a wave?

[@sheastewart7608]

For me, I often envision the electric field of the photon/light ray resonating with dipoles. The concept of a photon then serves to discretize the oscillating E field.

[@jlo13800]

Yes light is a quantum electron/positron twirling around each other!

[@glowaves]

I behave like a wave.

[@CrapE_DM]

My explanation with the polarizing lenses would be that the polarized lense can tilt the polarization of the photon a tiny bit, thus spinning some of them to the point that they now are able to go through the next lense, potentially turning some more.

[@badoem5353]

I don't think anything but gravity can affect spin in the way you mean it. Like you mean like spin on a ball right? Light goes straight only as far as I know. Mostly cause it'll be absorbed or reflected into or of wathever it touches. Unless there a partical that doesn't interact with light of course

[@hamishahern2055]

@@badoem5353 no, you need to think of spin as 360degress of pi. we break it up into 360 to make it easy on our maths. but you could as easily break it up into 36000 degrees in 2 pi radians.

[@Klaus293]

I’m so glad that we have this crazy stuff to ponder.

[@user-ns7mz1ld9u]

It makes me think of observing the pixels on a screen when illuminated and observing the electricity that flows to each pixel. The most likely answer is we're in a simulation similar to a video game, until the choice is made options are available

[@Markfr0mCanada]

You're a great science educator, and have a good voice for the role, but I feel that "Let's shed some light on light itself" might have sounded more epic if said by anyone else. It's such a badass line, but you're so soft spoken. Oh well, I'll keep watching now.

[@lifefordummies]

I feel like if we can ever figure out light it will unlock the greatest inventions of our species

[@GregoryJByrne]

magnetism. Explain to me how the New moon is lit when it is on the sun's side of the earth. Because the New Moon is on the centre of the galaxies side which either pulls or powers the earth's double torus magnetosphere out lighting the new moon. The New Moon is also the cause trigger that pulls Noah's floods out & around the [planet. You are are not God's. You can no more change the climate of this planet than you can change your God given gender. The precession of the Sun's shadow equinoxes not you or CO2 is causing these the climate change END TIMES Jesus warned us about with the Mystery of the 7 stars he held in his hand. Which we as disciples are supposed to use our double edged sword/tongue to warn humanity.

[@xenan1260]

And even Gravity*

[@awen9164]

We made wine enturies ago

[@jedison2441]

@@awen9164 Exactly how many enturies ago?

[@persona250]

@@xenan1260light , time and gravity all linked , solve one

[@markazcpa3]

This is the best explanation I has seen of this concept if you can call it that.

[@AndyWitmyer]

The strange properties of light - and all energy at the quantum level - are why I lean towards the idea that our universe is some kind of simulation.

[@dipaoloboat]

It is a creation, God created it. It all fits perfectly.

[@michaelgrey7854]

@@dipaoloboat Nah. God is a construct of humans.

[@Overitall805]

There is much much more going on at the quantum level than we have an awareness of yet.

[@DanielVerberne]

I've never properly understood what is meant by 'observing' a quantum property. What constitutes an observer? A device? A human at end of said device? A randomly-thrown die mapped to the use of a device? I realise much of this is statistical, but doesn't mean I find any of them quantum world satisfying.

[@Pyriold]

@@DanielVerberne The term observer is misleading. Really, any interaction counts as an observer as far as i know.

[@thekidwhodraws]

@@DanielVerberne in order to “observe” a photon, you have to absorb some of its energy. It has to be reoriented by your sensor or absorbed by your eyeball or redirected by a surface, all of which change the quantum properties of that photon. So once you “observe” the photon, you have altered its properties, and it has been changed. It has nothing to do with consciousness, which is why it doesn’t matter if it’s observed by a sensor or a person or even an interaction with another particle

[@SteedRuckus]

@@thekidwhodraws that's a really great explanation of that concept, which isn't exactly inherently understandable when the words "observe* or "observer" are involved.

[@helifynoe9930]

Well if the axis of the spin of a photon extends across both space and time, fascinating things would happen. The photon, due to this 4D axis, would also move back and forth across time, and its orientation would rotate during this process. This would help you understand how when two filters are at a 45 degree angle relative to each other, a measure of light still passes through, even though their polarities are not in line with each other. See if you can figure the rest out yourself.

[@jasondashney]

If a photon spun, then it couldn't really be a wave, could it? The quantum world hurts my tiny brain.

[@mcgarrydware]

I would suggest all waves have Wave Particle duality as all waves are a disturbance travelling through a set of particles. I would be interested to know if any of these experiments have been done with sound waves and with what results.

[@nerd26373]

This channel is always the best at what they do. We wish them well.

[@andreapacumaro1616]

There’s another one: SEA

[@GraveyardTricks]

Every channel is the best at what they do, because they're the only ones doing it.

[@ShawnGradybooks]

Thanks, Astrum. I am curious what your thoughts are on the De Broglie-Bohm interpretation of this (pilot-wave theory) and how they respond to the non-wave pattern result when the photons are observed/measured one at a time versus the wave pattern result when the photons are not observed/measured when sent one at a time.

[@guyincognito.]

Hidden variable theories are as garbage as the Copenhagen interpretation which introduced the 'collapse' assumption for which there is no empirical reason to believe.

[@Overlord7307]

5:25 sending more photons = increasing intensity, not increasing frequency. Increasing the frequency means to have photons with more energy due to the relation E = h(nu).

[@rayraycthree5784]

I think of light just like other electromagnetic energy, a frequency in the space time medium. Our eyes, plants, other materials absorb and/or reflect specific frequency just like antennas or reflectors. The 45 degree polarized filter probably just reorientates some of the vertically or horizontally polarized light impinging on it as does the third filter which is now at 45 degrees to the 2nd filter.